Rough idle/Misfire on cold startup

[Chavoos]

Hi Guys

Need some advice.
I get a rough idle sometimes after the car has sat overnight. I also have gotten a couple misfire codes to go along with this. Not sure what the issue is.
After the car warms up a bit , it runs fine.

Plugs have about 15000km on them.
From my limited experience, faulty coils usually misfire when the engine is hot.

I've done some internet searching and there seems to be a few culprits.

The most likely appears to be leaky injectors. Here is a link .
http://www.bimmerfest.com/forums/showthread.php?t=596197

2nd maybe the hpfp. Will run a log to check this.

Is it possible for a leaking valve cover gasket to drip oil to the plugs?

Is there a way to test injectors without removing?

Any help will be appreciated.


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[Prev]

Pull the plugs after the car has sat overnight and check if they are wet with fuel........that's how I checked my injectors were leaking. Got all 6 of them changed by BMW under motorplan. :thumbs:

 

[Chavoos]

Thanks Prevan.
I will try that next weekend.

Unfortunately I am not that lucky, no MP :thumbdo:

 

[Prev]

Thanks Prevan.
I will try that next weekend.

Unfortunately I am not that lucky, no MP :thumbdo:

Chat to Kish2604 as I believe he has some good injectors for sale :thumbs:

 

[Kish2604]

Chavs... Prevan is spot on with the directions... Let the car sit overnight and pull plugs without starting the next morning, the wet ones are shot! Let me know what you find, I might be able to hook you up injectors...

 

[Chavoos]

So I checked my plugs this morning.
I have a leaking valve cover gasket which is causing oil to seep on to some plugs, which makes checking for wet plugs due to fuel leaking a bit more difficult.

My analysis so far:
Plug check:
1: dark black no wet fuel.

2. Wet plug - top n bottom .. Not sure if it's oil or fuel due to leaking valve cover gasket . Reinstalled plug removed again after about an hour, there is a Dry bit in between top (thread) and bottom of plug (prongs).

3. Oil seeping till halfway the plug. But one of the 3 prongs is slightly wet.

4. Ok
5. Ok
6. Ok

I am thinking that I should replace the tappet cover gasket, put in new plugs and then monitor for fuel injector leak. ?





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[Prev]

Good plan Chavs


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[LFC]

I had rough starts and long cranks, particularly in the mornings.

HPFP replaced under MP and no issues for now.